Silicone-modified polyester resin and silicone-sheathed polyester fibers made therefrom

ABSTRACT

Polyester resin is modified with siloxane block polymers in such a manner so as to form silicone-modified polyester copolymer domains of controlled size and distribution dispersed in the polyester matrix. These domains undergo microphase segregation and migration during the melt spinning and cold-drawing to the surface of the polyester fiber being formed so as to provide a silicone-sheathed polyester fiber.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to polyester resins which have been modified withsiloxane block polymers to obtain copolymers with discrete siliconeblocks. The resulting silicone-modified polyester resins maintain thephysical properties of a polyester resin and yet subsequent processingexhibits the surface properties of a silicone sheathed material. Theinvention also relates to fibers made from the silicone-modifedpolyester resin and their use in a variety of products.

2. Prior Art

Polyesters have been characterized as heterochain macromolecularcompounds that possess a plurality of carboxylate ester groups ascomponents of their skeletal structure as distinguished from otherester-containing polymers, such as cellulose esters, poly(acrylates) andpoly(vinyl esters) which have carboxylate groups forming part ofpendants from the skeletal structure. Polyesters have found wideutility, being used as fibers, films, plasticizers and polyurethaneintermediates to name but a few applications.

Although many reactions are possible for the synthesis of polyesters,conventionally the polyesterification of dicarboxylic acids or theirfunctional derivatives with diols followed by a polycondensationreaction is most widely utilized.

Despite being suitable for many applications, polyesters have beentreated with a variety of additives to enhance their physicalproperties. Silicone has found many uses in conjunction with polyesters,including hydrolytic stability, lubricity, water repellancy and thelike. Traditionally, these silicones were applied topically to thefinished polyester, see for instance U.S. Pat. No. 4,105,567. However,there has continually been an effort to modify the polyester resinitself in such a way as to provide the polyester resin with theproperties of the silicone without adversely affecting its physicalcharacteristics.

An early attempt at such a modification was U.S. Pat. No. 3,296,190where polyesters were modified with a carbodiimide and a silicone in aneffort to stabilize the ester groups from hydrolysis.

Shortly thereafter, two related patents by Union Carbide Corporation,U.S. Pat. Nos. 3,579,607 and 3,701,815, sought to modify the polyesterwith silicone blocks. This work, as it relates to fibers, suffered fromtwo drawbacks, nitrogen contained in the siloxane blocks was releasedduring copolymerization and discolored the resulting polyester resin andthe large amount of silicone employed adversely affected the ability toprocess fibers.

Polyethylene terephthalate was reported as one of the polymericmaterials that could be modified by dispersing polysiloxanes containingpolymerized vinyl units, such as styrene, in the preformed organicpolymer in U.S. Pat. No. 3,691,257. This patent noted that surfacemodification of the polymeric material is obtainable and more permanentin nature over topical treatments or simple mixtures when the polymericmaterial is chemically modified with polysiloxanes.

In U.S. Pat. Nos. 3,674,724 and 3,749,757 polyesters for reinforcedelastomers were manufactured by reacting a polycarboxylic acid and apolyol with either an organosilane or a polysiloxane. Thesilicone-containing material was utilized to provide additional sitesfor crosslinking the polymeric material to obtain improved tensilestrengths under high load.

Acrylic and methacrylic esters were modified with polysiloxanes in U.S.Pat. No. 4,153,640 to obtain modified polymers suitable for treatingfibrous materials, including textiles, in an attempt to offer theadvantage of water repellancy.

Most recently, a team of scientists at Goodyear Tire and Rubber Companyhave explored silicone-modification of polyester films as a means toimprove the slip characteristics of such films, see U.S. Pat. Nos.4,348,510, 4,452,962 and 4,496,704. These films are designed to exhibitimproved optical clarity for use in visual applications. Here, thesilicon atom distribution is inhomogeneous (i.e., there will be localconcentrations of dimethylsiloxy mers) while the silicone blockdistribution is random and hence homogeneous. This type of incorporationwill not favor migration of the silicone domains to the surface and canbe expected to alter the bulk physical properties of the polyester resinso formed.

Despite numerous references to silicone-containing materials beingutilized to modify polyesters in an effort to realize thecharacteristics obtainable when these same polyesters are treatedtopically with silicone-containing materials, there continues to be aneed for a modified polyester having these attributes which does notsuffer from a reduction in its physical properties as a result ofincorporating blocks of silicone-containing material into the skeletalstructure.

OBJECTIVES OF THE INVENTION

It is a primary object of the present invention to provide asilicone-modified polyester resin where the silicone-containing unitsare capable of undergoing controlled microphase segregation within thepolyester matrix.

It is another object of the present invention that thesilicone-containing units be distributed within the polyester matrix insuch a manner so that their size and location will not adversely affectthe physical properties of the finished polyester.

A further object of the present invention is that the silicone-modifiedpolyester resin be capable of being formed into fibers. These fibersshould exhibit improved fiber characteristics relative to fibers madefrom unmodified polyester, such as lower surface energy, greaterlubricity, improved soil release, enhanced softness, greater permanencyof the silicone-containing material and the like.

SUMMARY OF THE INVENTION

The present invention provides a silicone-modified polyester resinhaving discrete domains within the polyester matrix ofsilicone-containing units derived from polysiloxane block polymers ofthe general formula ##STR1## wherein R is individually a monovalentgroup selected from the group consisting of alkyl, aryl, acyl, aralkyland polyoxyalkyl;

R' is individually an alkyl, aryl, alkenyl, or aralkyl group containingfrom 1 to 8 carbon atoms;

a has a value of 0 to 10;

b has a value of 0 to 50,000;

c has a value of 0 to 1,000; with the proviso that there must be atleast 10 silicon atoms in the polysiloxane block polymer;

x has a value of 0, 1, 2 or 3; and

Z is selected from the group consisting of alkyl, aryl, aralkyl, alkoxy,siloxy, acyl, alkenyl and polyoxyalkyl.

The instant invention also provides for fibers made from thesilicone-modified polyester resin and those products and uses to whichsuch fibers would advantageously be utilized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a depiction of an unmodified polyester resin.

FIG. 1B is a depiction of a fiber made from the unmodified polyesterresin shown in FIG. 1A.

FIG. 2A is a depiction of a silicone-modified polyester resin that haduncontrolled phase segregation resulting in a widely disparatedistribution and size of the silicone-containing domains.

FIG. 2B is a depiction of a fiber made from the silicone-modifiedpolyester resin shown in FIG. 2A. The fiber exhibits slubs.

FIG. 3A is a depiction of a silicone-modified polyester resin withcontrolled phase segregation resulting in discrete silicone-containingdomains having uniform distribution and size.

FIG. 3B is a depiction of a fiber made from the silicone-modifiedpolyester resin shown in FIG. 3A. The fiber exhibits a silicone sheath.

FIG. 4A is a depiction of a silicone-modified polyester fiber withcontrolled phase segregation resulting in discrete silicone-containingdomains having uniform distribution and size where thesilicone-containing units making up such domains have specializedpendant groups for performing specific tasks.

FIG. 4B is a depiction of a fiber made from the silicone-containingpolyester resin shown in FIG. 4A. The fiber has pendant groups attachedto the silicone sheath.

FIG. 5 illustrates a cross-sectional perspective of thesilicone-modified polyester resin having polysiloxane block polymerdispersed within a polyester matrix and encapsulated by asilicone-modified polyester copolymer.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, there is provided asilicone-modified polyester resin. The silicone-modified polyester resincan be prepared by conventional processes and techniques employed in theproduction of unmodified polyester resins. These processes include theolder batch process of a catalyzed ester-exchange reaction, a continuouspolymerization utilizing an ester-exchange column or adirect-esterification processes. Thus, the modified polyesters areprepared by first subjecting the mixture of reactants from which theyare derived to either transesterification or esterification reactionconditions followed by subsequent polycondensation of either thetransesterfication or esterification reaction product. In general, thetransesterification reaction, involving reaction between a dialkyl esterof a dicarboxylic acid and glycol will be conducted at elevatedtemperatures ranging from about 170° C. to about 205° C. and preferablyfrom about 185° C. to about 200° C. under an inert gas atmosphere suchas nitrogen. In addition, a catalyst will usually be employed to promotethe transesterification reaction such as soluble lead and titaniumcompounds, representatives of which include litharge, lead acetate,glycol titanates, and the like, as well as other well knowntransesterification catalysts such as compounds of zinc, magnesium,calcium and manganese. In many instances, the zinc and maganesecompounds may be preferred.

The esterification reaction involving the reaction between a freedicarboxylic acid and a glycol with the evolution of water also iscarried out at elevated temperatures and, in addition, at elevatedpressures employing inert gas atmospheres. Usually, the reactiontemperatures will range from about 220° C. to about 270° C. andpressures from about 30 to about 40 pounds per square inch (2.0-3.0kilograms per square centimeter). The reaction can be carried out eitherin the presence or absence of catalysts. When catalysts are employed,those normally indicated in the art as being useful include compounds ofmetals such as zinc, lead, antimony, manganese, zirconium, and the like.The reaction can also be carried out in the presence of a low molecularweight polymeric solvent such as described in U.S. Pat. No. 4,020,049.

The polycondensation reaction, the final preparation step in theproduction of the silicone-modified polyesters of the present invention,is also carried out employing well known techniques and conditions.Thus, in the polycondensation step, elevated temperatures, reducedpressures and inert atmospheres are utilized during the polymerizationof the transesterification or esterification reaction product to thedesired final product. Temperatures employed in this reaction step willgenerally range from about 260° C. to about 300° C. and preferably fromabout 270° C. to about 285° C. while pressures will range from about 1.0to 0.1 millimeters of mercury pressure. Catalysts useful in promotingthe polycondensation include, in addition to the soluble lead andtitanium catalysts noted above, various known compounds of antimony,niobium, germanium and the like. Normally, these catalysts will be addedto the transesterification or esterification reaction product when theformation of said product is fairly complete and before thepolycondensation step is begun.

The critical reactants include an aromatic dicarboxylic acid or itsdiester, a diol, and a siloxane block polymer.

Suitable aromatic dicarboxylic acids include those having from 8 to 15carbon atoms or the C₁ to C₄ dialkyl esters thereof. Representativeexamples of such aromatic dicarboxylic acids include, but are notlimited to, terephthalic acid, dimethylterephthalate, phthalic acid,isophthalic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyl dicarboxylic acid and4,4'-sulfonyldibenzoic acid. It is preferred that symmetrical aromaticdicarboxylic acids be employed, most preferably terephthalic acid.

Suitable diols include those having from 2 to 20 carbon atoms.Representative examples of such diols include, but are not limited to,

(a) aliphatic diols such as ethylene glycol, diethylene glycol,propylene glycol, 1,4-butanediol, 1,8-octanediol, decamethylene glycoland the like;

(b) branch chain diols such as neopentyl glycol, 2-methyl-2-ethylpropane diol-1,3 and 2,2-diethyl propane diol-1,3;

(c) cycloalkane diols such as cyclohexane dimethanol;

(d) bis-(hydroxyphenyl)alkanes such as 2,2-bis-(4-hydroxyphenyl)propane,

2,4'-dihydroxydiphenyl-methane,

bis-(2-hydroxyphenyl)methane,

bis-(4-hydroxyphenyl)methane,

bis-(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)methane,

1,1-bis-(4-hydroxyphenyl)ethane,

1,2-bis-(4-hydroxyphenyl)ethane,

1,1-bis-(4-hydroxy-2-chlorophenyl)ethane,

1,1-bis-(3-methyl-4-hydroxyphenyl)propane,

1,3-bis-(3-methyl-4-hydroxyphenyl)propane,

2,2-bis-(3-phenyl-4-hydroxyphenyl)propane,

2,2-bis-(3-isopropyl-4-hydroxyphenyl)propane,

2,2-bis-(2-isopropyl-4-hydroxyphenyl)propane,

2,2-bis-(4-hydroxynaphthyl)propane,

2,2-bis-(4-hydroxyphenyl)pentane,

3,3-bis-(4-hydroxyphenyl)pentane,

2,2-bis-(4-hydroxyphenyl)heptane,

bis-(4-hydroxyphenyl)phenylmethane,

2,2-bis-(4-hydroxyphenyl)-1-phenylpropane,

2,2-bis-(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane and the like;

(e) di(hydroxyphenyl)sulfones such as bis-(4-hydroxyphenyl)sulfone,2,4'-hydroxydiphenyl sulfone, 5'-chloro-2,4'-dihydroxydiphenyl sulfone,5'-chloro-4,4'-dihydroxydiphenyl sulfone, and the like; and

(f) di(hydroxyphenyl)ethers such as bis-(4-hydroxyphenyl)ether, the4,3'-, 4,2'-, 2,2'-, 2,3'-dihydroxydiphenyl ethers,

bis-(4-hydroxy-3-isobutylphenyl)ether,

bis-(4-hydroxy-3-isopropylphenyl)ether,

bis-(4-hydroxy-3-chlorophenyl)ether,

bis-(4-hydroxy-3-fluorophenyl)ether,

bis-(4-hydroxy-3-bromophenyl)ether,

bis-(4-hydroxynaphthyl)ether,

bis-(4-hydroxy-3-chloronaphthyl)ether,

4,4'-dihydroxy-3,6-dimethoxydiphenyl ether,

4,4'-dihydroxy-2,6-dimethyldiphenyl ether,

4,4'-dihydroxy-2,5-diethoxydiphenyl ether and the like.

Suitable siloxane block polymers are represented by the general formula##STR2## wherein R is individually a monovalent group selected from thegroup consisting of alkyl, aryl, acyl, aralkyl and polyoxyalkyl. Rcannot be hydrogen. This R group will ultimately be liberated to form analcohol in the first stage of the preparation of the silicon-modifiedpolyester resin and thus, in some instances, it may be desirable thatthe alcohol so formed be capable of removal by distillation. In thoseinstances it is preferred that R contain no more than 18 carbon atoms,more preferably 12 carbon atoms or less. In one aspect of the presentinvention, the proper choice of the R group will affect the solubilityof the siloxane block polymer in the nascent polyester matrix. In thoseinstances where the solubility of the siloxane-block polymer is aconcern, the R group needs to be oleophilic in nature. Illustrative ofsuch oleophilic R groups are 2-ethylhexyl, decyl, benzyl andpolyoxypropyl;

R¹ is individually a monovalent group selected from the group consistingof alkyl, aryl, alkenyl and aralkyl groups containing from 1 to 8 carbonatoms. Once again, when solubility is a concern the R¹ pendant groupshould be oleophilic in nature, such as phenyl, phenethyl or ethyl;

Z is selected from the group consisting of alkyl, aryl, aralkyl, alkoxy,polyoxyalkyl, alkenyl and siloxy with the proviso that when Z is siloxyx must equal zero. The Z group preferably contains from 1 to 25 carbonatoms, more preferably from 1 to 15 carbon atoms. The Z group may besubstituted or unsubstituted, with halogen, cyano, amino, carboxy,sulfonate, alkylmercapto and hydroxy groups the preferred substituents.In those instances where Z is substituted with an amino, carboxy orhydroxy group the value of a should be 3 or less to avoid unwantedcrosslinking. Another aspect of the invention requires that in someinstances, Z be an oleophilic group so as to enhance the solubility ofthe polysiloxane block polymer in the nascent polyester matrix;

a has a value of 0 to 10, preferably 0 to 5;

b has a value of 0 to 50,000, preferably 10 to 10,000 and mostpreferably 50 to 200;

c has a value of 0 to 1,000, preferably 0 to 100; and

x has a value of 0, 1, 2 or 3.

The value of a, b, and c should be such that the polysiloxane blockpolymer contains at least 10 silicon atoms, preferably at least 50silicon atoms.

Suitable siloxane block polymers and modified block polymers include butare not limited to, diethoxy polydimethylsiloxane,

bis-(2-ethylhexyloxy)polydimethylsiloxane,

bis-(hydroxyethyloxy)polydimethylsiloxane,

bis-(butyroxy)polydimethylsiloxane,

dibenzyloxy polydimethylsiloxane,

didodecyloxy polydimethylsiloxane,

diethoxy poly(dimethyl)(methylethyl)siloxane,

diethoxy poly(dimethyl)(methylbutyl)siloxane,

diethoxy poly(dimethyl)(dihexyl)siloxane,

diethoxy poly(dimethyl)(methyl phenyl)siloxane,

dibutoxy polydiethylsiloxane,

diphenoxy poly(dimethyl)(methylhexyl)siloxane,

bis-(2-ethylhexyloxy)poly(dimethyl)(methyl octyl)siloxane,

diethoxy poly(dimethyl)(methylhexyl)(methyl octadecyl)siloxane,

diethoxy poly(dimethyl)(methyl chloropropyl)siloxane,

diethoxy poly(dimethyl)(methyl morpholinopropyl)siloxane,

diethoxy poly(dimethyl)(methyl cyanopropyl)siloxane,

diethoxy poly(dimethyl)(methyl trifluoropropyl)siloxane,

diethoxy poly[dimethyl][methyl(butoxyethyloxy)propyl]siloxane,

diethoxy poly[dimethyl][methyl][methoxy(triethyloxy)propyl]siloxane,

diethoxy poly[dimethyl][methyl poly(propyloxy)propyl]siloxane,

bis(methoxyethyloxy)poly(dimethyl)(methylbutyl)siloxane,

tetraethoxy bis(methyl)polydimethylsiloxane, and

triethoxy(decyl)polydimethylsiloxane.

The relative amount of each reactant to one another is of criticalimportance. This is especially true of the siloxane block copolymerreactant since too much will adversely affect the physical properties ofthe polyester whereas too little will not provide the surfacecharacteristics desired. Thus, relative to the aromatic dicarboxlicacid, the diol should be present in either a stoichometric amount or inexcess, it being preferred to utilize an excess of the diol. Thesiloxane block copolymer should be present in an amount sufficient toobtain from 0.1 to 10 weight percent, based on the total reactionproduct, of silicone-containing units in the polyester matrix preferably0.5 to 5 weight percent.

The resulting silicone-modified polyester resin is believed to containfrom two to three separate regions, a polyester matrix comprising thereaction product of the aromatic dicarboxylic acid and diol;microdomains of polysiloxane block polymers dispersed within thepolyester matrix, which in preferred embodiments are so small as to beconsidered absent altogether; and silicone-modified polyester forming abarrier region between the microdomains dispersed within polyestermatrix and the polyester matrix itself.

The distribution and size of the silicone domains within the polyestermatrix are essential to the polyester resin and the fiber madetherefrom. As previously noted, if the size is too large, the physicalproperties of the polyester are adversely affected, if too small, thepolyester does not exhibit the distinguishing characteristics over anunmodified polyester resin. In addition, the presence of the disperseddomains provides a delustering of the resin. The size and distributioncan be controlled by three known parameters although other methods maybecome apparent to those skilled in the art. First, by providing highspeed agitation during the polyester formation the size of the siliconedomains is reduced and uniformly dispersed within the polyester matrix.The agitation rate should be increased approximately five fold over whatwould be necessary for an unmodified polyester resin. Secondly, byproper choice of the endblock on the siloxane block polymers, thesolubility of the polysiloxane block polymer within the nascentpolyester matrix can be enhanced. Thus oleophilic end groups arepreferred. The greater the solubility, the smaller and more uniform thesize and distribution of the silicone-containing domains. Finally, theskeletal structure of the siloxane block polymer can be modified byattaching pendant groups to enhance its solubility. Despite desiringincreased solubility, too much solubility will generate such smalldomains that the beneficial characteristics silicone-modificationprovides will not be apparent. The silicone-containing domains shouldnot exceed one-fourth the size of the spinneret opening. In practice, itis believed the silicone-containing domains should be from about 0.05microns to 6 microns in average size, preferably about 0.1 to 1 microns.

The silicone-modified polyester resin can be chipped to form pellets formelt spinning at a later time or can in some continuous systems besubjected to direct melt spinning. In either event, spinning is requiredto take the silicone-modified polyester resin and turn it into apolyester fiber. Melt spinning consists of extrusion through a capillaryto form a filamentary stream followed by stretching and cooling of thefiber so made. It is during the extrusion stage of fiber formation thatsome of the advantages of having a silicone-modified polyester resinfirst become apparent.

By careful control of the size and distribution of thesilicone-containing domain, migration of the domain within the polyestermatrix initially takes place during the extrusion stage. Here themicrodomain migrates to the outside of the forming fiber releasing theentrapped polysiloxane block polymer to the interface akin to a topicalfinish of silicone lubricants. At the same time, the silicone-modifiedpolyester which has encapsulated the polysiloxane block polymer domainsalso migrates to the outside of the forming fiber to create asilicone-modified polyester sheath around the polyester matrix. Thissheath, being chemically bound to the rest of the polyester fiber,provides a permancy for those silicone-related characteristics to thefiber. If the domains are large, the center region of the domain willcontain polysiloxane block polymer which is not chemically linked to thepolyester matrix. This free polysiloxane block polymer will potentiallybe lost to solvent extraction. Also, if the domain is too large (i.e.,on the order of the fiber diameter) it will interfere with melt spinningby either causing a slub-like structure or, in the extreme, cause fiberbreakage. Preferably, the domains are small enough so that the endgroupsof all of the polysiloxane block polymer have an opportunity to condensewith the polyester, thus no free polysiloxane block polymer would bepresent but rather only copolymer between the polyester matrix andsiloxane block copolymer. Although it is known that silicone, having alow surface energy, will preferentially occupy a surface geometry andthus tend to migrate to the air-solid or air-liquid interface whenpresent, the art suggests that for the silicone to migrate in such amanner it needs to be free, that is, not chemically bound to the matrix.Thus, it was totally unexpected that, in contrast to these expectations,the silicone-modified polyester heterogenite would be capable ofmigration.

The melt spinning operation utilized is conventional and, as such, istypically characterized by forcing the silicone-modified polyester resinat a temperature above its melting point, but below so high atemperature as to favor thermal degradation, such as 250° C. to 350° C.,through a sand-bed filter to a steel spinneret containing openings. Theresin throughput is controlled by a gear pump which is capable of alsogenerating the necessary pressure required to force the polymer throughthe filter-spinner assembly. The extruded fiber is then stretched toobtain an ordered crystalline structure and cooled, usually by a forcedair quench system. Surprisingly, the migration of the silicone domainshas been found to continue during the drawing, including cold drawing,of the fiber where the fiber is much more solid than in themelt-spinning operation. The silicone-modified polyester fiber so madeshould have a weight average molecular weight in the range of 10,000 to200,000, preferably in the range of 15,000.

The silicone-modified polyester fiber produced in accordance with thepresent invention finds utility in a number of diverse applications.Staple, cut from tow, represents one of the largest usessilicone-modified polyester fibers can be employed in. Here blends ofthe silicone-modified polyester fiber may be made with either cotton orwool. Yarns are another important area where silicone-modified polyesterfibers can be utilized, in particular industrial yarns for automobiletires, safety belts, fire hoses and the like or textile filament yarnsfor knitted or woven fabrics. Fiberfill is yet another application inwhich silicone-modified polyester fibers in staple or tow form will findutility in sleeping bags, pillows, garment insulation and the like.Other areas of potential use include carpet fiber, shoe linings,electrical insulation, diaper coverstock and the like.

Another aspect of the present invention provides a silicon-modifiedpolyester resin or fiber having reactive pendant groups available on itssurface for subsequent reaction with other chemicals or substances. This"lock and key" approach allows the polyester to have a pendant modifyinggroup chemically bonded to it (the "lock") which can interact with anyof a variety of chemicals or substances (the "key") to alter the fibersproperties, i.e., dyes, flame retardants, lubricants, etc.

Whereas the exact scope of the instant invention is set forth in theappended claims, the following specific examples illustrate certainaspects of the present invention and, more particularly, point outmethods of evaluating the same. However, the examples are set forth forillustration only and are not to be construed as limitations on thepresent invention except as set forth in the appended claims. All partsand percentages are by weight unless otherwise specified.

EXAMPLE A Unmodified Poly(ethylene terephthalate) Resin

A glass reactor was equipped with a mechanical stirrer (model HST 20; G.K. Heller Corp.,) condenser, and nitrogen sparge. To this reactor wascharged 737 grams of dimethylterephthalate (DMT) and 585 grams ofethylene glycol (EG). Then, 0.22 grams of manganese acetate and 0.29grams of antimony trioxide were added as catalysts. Using an oil bathfilled with UCON™ HTF-30 (Union Carbide, Danbury, Conn.), reactortemperature was raised to 180°-185° C. and maintained at thistemperature for approximately 2.5 hours to effect transesterification.After 2.5 hours, approximately 85 percent of the theoretical quantity ofmethanol had been trapped in the distillation receiver, which was cooledwith dry ice/acetone. Percent methanol was determined by refractiveindices of distillate corrected for EG contamination. Once approximately85 percent of the theoretical methanol had been collected, thetemperature was raised to 240° C. and maintained for approximately 1hour. At the end of this interval, an additional 15 percent oftheoretical methanol had been collected. Thus, at the end oftransesterification, approximately 100 percent of theoretical methanolhad been collected. At this point, after the nitrogen sparge andreceiver containing methanol were removed, the mechanical stirrer wasturned on and adjusted to a speed of 50 rpm. A fresh distillationreceiver was attached to the reactor system. Then, pressure wasgradually reduced to approximately 0.5 mm Hg while reaction temperaturewas raised to 280° C. After approximately 150 minutes, stirrer torquehad increased from 3.5 pounds-inch to 5.8-6.0 pounds-inch. Reactionpressure was then raised to atmospheric by bleeding in nitrogen. Theintrinsic viscosity of this resin (measured in a solvent of 1 part byweight of trifluoroacetic acid and 3 parts by weight of dichloromethane)was 0.63.

EXAMPLE B Synthesis of ##STR3##

A five-liter three-neck flask was equipped with the following: (1)thermometer equipped with a Thermo-watch™ temperature controller, (2)reflux condenser, (3) positive nitrogen pressure system, (4) mechanicalstirrer. To this apparatus, 373 grams of ##STR4##

2627 grams of cyclooctamethyltetrasiloxane (tetramer) and 30 grams oftetramethylammonium hydroxide were charged and maintained at 95° C. forapproximately 16 hours. Then, the reaction temperature was raised to150° C. for one hour and purged with nitrogen for 4 hours. Therefractive index of the final product was 1.403 at 25° C. With aBrookfield Viscometer (Model LUT; spindle #2 at 60 rpm), the viscositywas 118 cps. Gel permeation chromatography indicated only one majorcomponent.

EXAMPLE C Synthesis of ##STR5##

The procedure of Example B was followed with the exception that thefollowing reactants were charged:

    ______________________________________                                        Cyclooctamethyltetrasiloxane                                                                           592 grams                                            (Tetramer)                                                                     ##STR6##                8.3 grams                                            Tetramethylammonium hydroxide                                                                          6.0 grams                                            ______________________________________                                    

EXAMPLE D Synthesis of ##STR7##

The procedure of Example B was followed with the exception that a2-liter flash was used. The following reactants were charged:

    ______________________________________                                        Cyclooctamethyltetrasiloxane                                                                           913    grams                                         (Tetramer)                                                                     ##STR8##                47     grams                                         Tetramethylammonium hydroxide                                                                          4.8    grams                                         ______________________________________                                    

The refractive index (25° C.) was 1.3954, viscosity was 772 cps. Gelpermeation chromatography indicated only one major component.

EXAMPLE E Synthesis of ##STR9## (a) (CH₃)₂ Si[O(CH₂)₃ CH₃ ]₂

Endblocker

A two-liter three-neck round bottom flask was equipped with a mechanicalstirrer, condenser, addition funnel and heating mantle. To the reactionvessel there was added 444 grams of n-butanol which was brought to atemperature of 40° C. Then, 258 grams of (CH₃)₂ Si(Cl)₂ were addeddropwise over a period of three hours. After the addition had beencompleted, the reaction mixture was allowed to stir for 12 hours at 22°C. Using atmospheric fractional distillation, 270 grams of product witha boiling point of 190°-192° C. was isolated. ##STR10##

The procedure of Example B was followed with the exception that thefollowing reactants were charged:

    ______________________________________                                        (CH.sub.3).sub.2 Si[O(CH.sub.2).sub.3 CH.sub.3 ].sub.2                                               913    grams                                           Tetramer               555    grams                                           Tetramethylammonium hydroxide                                                                        6.0    grams                                           ______________________________________                                    

The refractive index was (25° C.) 1.405; viscosity was 93 cps. Gelpermeation chromatography indicated only one major component. Nuclearmagnetic resonance (NMR) indicated the structure of the final productwas ##STR11##

EXAMPLE F Synthesis of ##STR12##

Endblocker

The procedure of Example E(a) was followed with the exception that thefollowing reagents were charged:

    ______________________________________                                        2-ethyl-1-hexanol                                                                             677 grams                                                     (CH.sub.3).sub.2 Si(Cl).sub.2                                                                 258 grams                                                     ______________________________________                                    

thereafter 494 grams of product with a boiling point of 141° C. (0.2 mmHg) were isolated by fractional distillation. ##STR13##

The procedure of Example E(b) was followed with the exception that thefollowing reactants were charged: ##STR14##

The final product's refractive index was (25° C.) 1.406; viscosity was110 cps. Gel permeation chromatography indicated only one majorcomponent. NMR indicated the structure of the final product was##STR15##

EXAMPLE G Synthesis of ##STR16## (a) (CH₃)₂ Si[O(CH₂)₂ O(CH₂)₂ OCH₃ ]₂

Endblocker

The procedure of Example E(a) was followed with the exception that thefollowing reactants were charged:

    ______________________________________                                        CH.sub.3 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2 OH                                                  937 grams                                                  (CH.sub.3).sub.2 Si(Cl).sub.2                                                                    387 grams                                                  ______________________________________                                    

thereafter 652 grams of product with a boiling point of 123°-125° C.(0.1 mm Hg) was isolated by fractional distillation. ##STR17##

The procedure of Example E(b) was followed with the exception that thefollowing reactants were charged:

    ______________________________________                                        (CH.sub.3).sub.2 Si[O(CH.sub.2).sub.2 O(CH.sub.2).sub.2 OCH.sub.3             ].sub.2                 29.6   grams                                          Tetramer                555    grams                                          Tetramethylammonium hydroxide                                                                         6      grams                                          ______________________________________                                    

The refractive index of the final product was 1.404; viscosity was 50.6cps.

EXAMPLE H Synthesis of ##STR18## (a) (CH₃)₂ Si[O(CH₂)₂ O(CH₂)₃ OCH₃ ]₂

Endblocker

The procedure of Example E(a) was followed with the exception that thefollowing reactants were charged:

    ______________________________________                                        (CH.sub.3).sub.2 Si(Cl).sub.2                                                                   129 grams                                                   CH.sub.3 (CH.sub.2).sub.2 O(CH.sub.2).sub.2 OH                                                  307 grams                                                   ______________________________________                                    

thereafter 222 grams (B.P. 190° C. at 28 in Hg) of final product wasisolated by fractional distillation. ##STR19##

The procedure of E(b) was followed with the exception that the followingreactants were charged:

    ______________________________________                                        (CH.sub.3).sub.2 Si[O(CH.sub.2).sub.2 O(CH.sub.2).sub.3 CH.sub.3 ].sub.2                             58.4   grams                                           Tetramer               1,100  grams                                           Tetramethylammonium hydroxide                                                                        11.7   grams                                           ______________________________________                                    

The refractive index (25° C.) was 1.406; viscosity was 115 cps. Gelpermeation chromatography indicated only one major component. NMRindicated the structure of the final product was: ##STR20##

EXAMPLE I Synthesis of ##STR21## (a) (CH₃)₂ Si[O(CH₂)₉ CH₃ ]₂

Endblocker

The procedure of Example E(a) was followed with the exception that thefollowing reactants were charged:

    ______________________________________                                        (CH.sub.3).sub.2 Si(Cl).sub.2                                                                  67 grams                                                     CH.sub.3 (CH.sub.2).sub.9 OH                                                                  165 grams                                                     ______________________________________                                    

thereafter 125 grams of product (B.P. 265° C. 25 in Hg) were isolated byfractional distillation. ##STR22##

The procedure of E(b) was followed with the exception that the followingreactants were charged:

    ______________________________________                                        (CH.sub.3).sub.2 Si[O(CH.sub.2).sub.9 (CH.sub.3 ].sub.2                                              37.3   grams                                           Tetramer               555    grams                                           Tetramethylammonium hydroxide                                                                        6      grams                                           ______________________________________                                    

The final product's refractive index was (25° C). 1.409; viscosity was99 cps.

EXAMPLE J Preparation of Modified Siloxane-Block Polymers

A round bottom flask was equipped with a mechanical stirrer and nitrogeninlet. The flask was charged with 414.0 grams ofoctamethylcyclotetrasiloxane, 88.8 grams of ##STR23## 119.0 grams ofhexamethyldiphenethylcyclotetrasiloxane and 3.0 grams oftetramethylammonium silanolate. After flushing with nitrogen thereaction mixture was heated to 90° C. and maintained at the temperaturefor 30 hours under nitrogen. The temperature was then increased to 150°C. for 1 hour. The temperature was decreased to 110° C. and thevolatiles were removed by vacuum. After cooling under vacuum to roomtemperature, the fluid was pressure filtered through a 0.1μ pad.

Gel permeation chromatography indicated only one major component. NMRindicated the structure of the final product was: ##STR24##

The index of refraction (25° C.) was 1.4225; viscosity was 150 cps.

EXAMPLE K Preparation of Modified Siloxane-Block Polymers

The procedure of Example J was followed with the exception that 300.6grams of cyclic tetramer, 59.1 grams of ##STR25##

65.9 grams of octaphenylcyclotetrasiloxane and 3.1 grams oftetramethylammonium silanolate were charged to the reaction flask. Gelpermeation chromatography indicated only one major component. NMRindicated the structure of the final product was: ##STR26##

The index of refraction (25° C.) was 1.4315; viscosity was 180 cps.

EXAMPLE L Preparation of Modified Siloxane Block Polymers

A round bottom flask was equipment with a mechanical stirrer andnitrogen inlet. The flask was charged with 266.4 grams of cyclictetramer, 13.1 grams of phenylmethyldiethoxysilane, 75 ml ethanol, 0.9grams potassium hydroxide, and 0.9 grams H₂ O. This mixture was refluxedunder nitrogen for 8 hours and then the ethanol was distilled off. Thetemperature of the reaction mixture was increased to 150° C. and stirredunder nitrogen for 20 hours. The reaction was cooled to 90° C. and 3.0grams of acetic acid was added and stirred for 1 hour. The volatileswere then stripped off by vacuum at 110° C. The fluid was cooled undervacuum and then pressure filtered through a 0.1μ pad.

Gel permeation chromatography indicated only one major component. NMRindicated the structure of the final product was: ##STR27##

The index of refraction (25° C.) was 1.4185; viscosity was 60 cps.

EXAMPLE M Preparation of Modified Siloxane Block Polymers

The procedure in Example L was followed except 213 grams of cyclictetramer, 10.0 grams of 3-cyanopropylmethyldiethoxysilane, 0.72 grams H₂O, 75 ml of CH₃ CH₂ OH and 1.2 grams KOH.

Gel permeation chromatography indicated only one major component. NMRindicated the structure of the final product was: ##STR28##

The index of refraction (25° C.) was 1.406; viscosity was 76 cps.

EXAMPLE N Preparation of Modified Siloxane Block Polymers

The procedure of Example J was followed with the exception that 174.6grams of cyclic tetramer, 35.5 grams of ##STR29## 28.8 grams oftetrahexyltetramethylcyclotetrasiloxane (prepared by the hydrolysis ofhexylmethyldichlorosilane) and 2.0 grams of tetramethylammoniumsilanolate were charged to the reaction flask. Gel permeationchromatography indicated only one major component. The structure of thefinal product was ##STR30##

The index of refraction (25° C.) was 1.4095; viscosity was 260 cps.

EXAMPLE O Preparation of Modified Siloxane Block Polymers

The procedure of Example J was followed with the exception that 174.6grams of cyclic tetramer, 35.5 grams of ##STR31## 34.4 grams oftetraoctyltetramethylcyclotetrasiloxane (prepared by the hydrolysis ofoctymethyldichlorosilane) and 2.0 grams of tetramethylammoniumsilanolate were charged to the reaction flask. Gel permeationchromatography indicated only one major component. The structure of thefinal product was ##STR32## The index of refraction (25° C.) was 1.408;viscosity was 140 cps.

EXAMPLE P Preparation of Modified Siloxane Block Polymer

The procedure of Example J was followed with the exception that 174.6grams of cyclic tetramer, 35.5 grams of ##STR33## 40.0 grams oftetradecyltetramethylcyclotetrasiloxane (prepared by the hydrolysis ofdecylmethyldichlorosilane) and 2.0 grams of tetramethylammoniumsilanolate were charged to the reaction flask. Gel permeationchromatography indicated only one major component. The structure of thefinal product was: ##STR34## The index of refraction (25° C.) was1.4158; viscosity was 96 cps.

EXAMPLE Q Preparation of Modified Siloxane Block Polymer

The procedure of Example J was followed with the exception that 218.3grams of cyclic tetramer, 44.4 grams of ##STR35## 57.0 grams oftetradodecyltetramethylcyclo tetrasiloxane (prepared by hydrolysis ofdodecylmethyldichloro-silane) and 2.0 grams of tetramethylammoniumsilanolate were charged to the reaction flask. Gel permeationchromatography indicated only one major component. The structure of thefinal product was: ##STR36## The index of refraction (25° C.) was 1.413;viscosity was 40 cps.

EXAMPLE R Preparation of Modified Siloxane Block Polymer

The procedure of Example J was followed with the exception that 130.9grams of cyclic tetramer, 26.6 grams of ##STR37## 46.8 grams oftetramethyltetraoctadecyclcylotetrasiloxane (prepared by hydrolysis ofmethyloctadecyclodichlorosilane) and 2.0 grams of tetramethylammoniumsilanolate were charged to the reaction flask. Gel permeationchromatography indicated only one major component. The structure of thefinal product was ##STR38## The index of refraction (25° C.) was 1.4195

EXAMPLE S Preparation of Modified Siloxane Block Polymer

The procedure of Example J was followed with the exception that 155.5grams of cyclic tetramer, 44.4 grams of ##STR39## 39.0 grams of(3,3,3-trifluoropropyl)methyl siloxane and 2.0 grams oftetramethylammonium silanolate were charged to the reaction flask. Gelpermeation chromatography indicated only one major component. Thestructure of the final product was ##STR40## The index of refraction(25° C.) was 1.4005; viscosity was 320 cps.

EXAMPLE T Preparation of Modified Siloxane Block Polymers

The procedure of Example L was followed with the exception that 103.6grams of cyclic tetramer, 56.1 grams of(heptadecafluoro-1,1,2,2-tetrahydrodecyl)-1-methyldichlorosilane, 50 mlof ethanol, 11.5 grams of potassium hydroxide and 0.29 grams of H₂ Owere charged to the reaction flask. Gel permeation chromatographyindicated only one major component. The structure of the final productwas: ##STR41## The index of refraction (25° C.) was 1.405; viscosity was320 cps.

EXAMPLE U Preparation of Modified Siloxane Block Polymers

The procedure of Example J was followed with the exception that 218.3grams of cyclic tetramer, 44.4 grams of ##STR42## 22.0 grams oftetramethyltetramethylcyclotetrasiloxane (prepared by the hydrolysis ofethylmethyldichlorosilane) and 2.0 grams of tetramethylammoniumsilanolate were charged to the reaction flask. Gel permeationchromatography indicated only one major component. The structure of thefinal product was ##STR43## The index of refraction (25° C.) was 1.4045;viscosity was 130 cps.

EXAMPLE V Preparation of Modified Siloxane Block Polymers

The procedure of Example J is followed with the exception that 261.9grams of cyclic tetramer, 53.3 grams of ##STR44## 30.6 grams oftetraallyltetramethylcyclosiloxane (prepare by the hydrolysis ofallylmethyldichlorosilane) and 2.0 grams of tetramethylammoniumsilanolate are charged to the reaction flask. Only one major componentis anticipated, the final structure of which is ##STR45##

EXAMPLE W Preparation of Modified Siloxane Block Polymer

The procedure of Example J was followed with the exception that 112.7grams of cyclic tetramer, 21.1 grams of ##STR46## 22.2 grams oftetramethyltetra-3-pyrollidinylpropylcyclo-tetrasiloxane prepared by thehydrolysis of 3-pyrollidinylpropylmethyl-dichloxysilane [(prepared bythe hydroxilylation of N-allypyrollidine amd diethoxymethylsilane)] and2.0 grams of tetramethylammonium silanolate were charged to the reactionflask. Gel permeation chromatography indicated only one major product.The structure of the final product was ##STR47## The index of refraction(25°) was 1.4165; the viscosity was 260 cps.

EXAMPLE X Preparation of Modified Siloxane Block Polymers

The procedure of Example J is followed with the exception that 261.9grams of cylic tetramer, 53.3 grams of ##STR48## 41.3 grams oftetra-(3-chloropropyl)tetramethylcyclotetrasiloxane (prepared by thehydrolysis of 3-chloropropylmethyldichlorosilane) and 2.0 grams oftetramethylammonium silanolate were charged to the reaction flask. Onlyone major component is anticipated, the final structure of which is##STR49##

EXAMPLE Y Preparation of Modified Siloxane Block Polymers

The procedure of Example J was followed with the exception that 56.5grams of cyclic tetramer, 13.6 grams of ##STR50## 18.0 grams oftetramethyltetra(butoxyethyloxy)propylcyclotetrasiloxane (prepared bythe hydrolysis of the hydrosilylation product of diethoxymethylsilaneand butoxyethyl oxyprop-1-ene and 1.0 grams of tetramethylammoniumsilanolate were charged to the reaction flask. Gel permeationchromatography indicated only one major component. The structure of thefinal product was ##STR51## The index of refraction (25° C.) was 1.4134;viscosity was 280 cps.

EXAMPLE Z Preparation of Modified Siloxane Block Polymers

The procedure of Example L was followed with the exception that 155.4grams of cyclic tetramer, 2.0 grams of potassium hydroxide, 50.7 gramsof methoxy(triethyloxypropyl)methyldiethoxysilane (prepared by thehydrosilylation of methyldiethoxysilane and allylmethoxytriglycol(AMTG)), 100 mls of ethanol and 21.6 grams of H₂ O were charged to thereaction flask. Gel permeation chromatography indicated there was onlyone major product. The structure of the final product was ##STR52## Theindex of refraction (25° C.) was 1.440; viscosity was 70 cps.

EXAMPLE AA Preparation of Modified Siloxane Block Polymers

The procedure of Example L was followed with the exception that 103.6grams of cyclic tetramer, 49.8 grams ofmethoxy(polyethyloxypropyl)methyldiethoxysilane (prepared by thehydrosilylation of methyldiethoxysilane and allyl(methoxypolyethyleneglycol)(APEG) 2.0 grams of potassium hydroxide, 75 mls. of ethanol and1.44 grams of H₂ O were charged into the reaction flask. Gel permationchromatography indicated only one major product. The structure of thefinal product was ##STR53## The index of refraction (25° C.) was 1.415;viscosity was 420 cps.

EXAMPLE BB Preparation of Modified Siloxane Block Polymers

The procedure of Example L was followed with the exception that 55.4grams of cyclic tetramer, 22.5 grams ofmethoxy(polypropyloxypropyl)methyldiethoxysilane (prepared by thehydrosilylation of methyldiethoxysilane and allyl(methoxypolypropyleneglycol) (APPG)), 0.5 grams of potassium hydroxide, 65 mls of ethanol and0.187 grams of H₂ O were charged to the reaction flask. Gel permeationchromatography indicated only one major product. NMR indicated thestructure of the final product was: ##STR54## The index of refraction(25° C.) was 1.411; viscosity was 300 cps.

EXAMPLE CC Preparation of Modified Siloxane Block Polymers

The procedure of Example J was followed with the exception that 136.5grams of cyclic tetramer, 26.6 grams of ##STR55## 15.5 grams oftetradodecyltetramethylcyclotetrasiloxane (prepared by the hydrolysis ofdodecylmethyldichlorosilane) and 2.0 grams of tetramethylammoniumsilanolate were charged to the reaction flask. Gel permeationchromatography indicated only one major product. The structure of thefinal product was ##STR56## The index of refraction (25° C.) was 1.4103;viscosity was 60 cps.

EXAMPLE DD Preparation of Modified Siloxane Block Polymers

The procedure of Example J was followed with the exception that 83.6grams of cyclic tetramer, 17.8 grams of ##STR57## 35.3 grams oftetradodecyltetramethylcyclotetrasiloxane (prepared by the hydrolysis ofdodecylmethyldichlorosilane) and 2.0 grams of tetramethylammoniumsilanolate were charged to the reaction flask. Gel permeationchromatography indicated only one major product. NMR indicated thestructure of the final product was: ##STR58## The index of refraction(25° C.) was 1.418; the viscosity was 180 cps.

EXAMPLE EE Preparation of Modified Siloxane Block Polymers

The procedure of Example J was followed with the exception that 130.9grams of cyclic tetramer, 26.6 grams of ##STR59## 23.4 grams oftetramethyltetraoctodecylcyclotetrasiloxane (prepared by the hydrolysisof octodecylymethyldichlorosilane), 10.8 grams oftetrahexyltetramethylcyclotetrasiloxane (prepared by the hydrolysis ofhexylmethyldichlorosilane) and 2.0 grams of tetramethylammoniumsilanolate were charged to the reaction flask. Gel permeationchromatography indicated only one major product. The structure of thefinal product was ##STR60## The index of refraction (25° C.) was 1.416;viscosity was 160 cps.

EXAMPLE FF Preparation of Modified Siloxane Block Polymers

The procedure of Example J is following with the exception that 204.2grams of cyclic tetramer, 11.4 grams of di(2-ethylhexy)dimethylsilane,45.6 grams of tetradodecyltetramethylcyclotetrasiloxane and 2.0 grams oftetramethylammonium silanolate are charged to the reaction flask. Theexpected structure of the final product is ##STR61##

EXAMPLE GG Preparation of Modified Siloxane Block Polymers

The procedure of Example K was followed with the exception that 226.7grams of cyclic tetramer, 59.1 grams of ##STR62## 158.5 grams ofhexamethyldiphenethylcyclotetrasiloxane and 2.1 grams oftetramethylammonium silanolate were charged to the reaction flask. Gelpermeation chromatography indicated only one major product. Thestructure of the final product was ##STR63## The index of refraction(25° C.) was 1.423; viscosity was 150 cps.

EXAMPLE 1 Silicone-modified-polyester Resin

The procedure of Example A was followed with the exception that 32.0grams of ##STR64## where charged with the other reactants and catalysts.The intrinsic viscosity of this resin was 0.60; elemental analysisindicated the presence of 3.5 weight percent silicone.

EXAMPLE 2 Silicone-modified-polyester Resin

The procedure of Example A was followed with the exception that 32.0grams of ##STR65## were charged with the other reactants and catalysts.the intrinsic viscosity of this resin was 0.60; elemental analysisindicated the presence of 3.0 weight percent silicone.

EXAMPLE 3 Silicone-modified-polyester Resin

The procedure of Example 2 was followed with the exception that stirrerspeed was increased to 250 rpm. The intrinsic viscosity of this resinwas 0.70; elemental analysis indicated the presence of 3.2 weightpercent silicone.

EXAMPLE 4 Silicone-modified-polyester Resin

The procedure of Example A was followed with the exception that 32.0grams of ##STR66## were charged. The intrinsic viscosity of this resinwas 0.51; elemental analysis indicated the presence of 3.8 weightpercent silicone.

EXAMPLE 5 Silicone-modified-polyester Resin

The procedure of Example A was followed with the exception that 32.0grams of ##STR67## where charged. The intrinsic viscosity of this resinwas 0.55; elemental analysis indicated the presence of 3.2 weightpercent silicone.

EXAMPLE 6 Silicone-modified-polyester Resin

The procedure of Example A was followed with the exception that 32.0grams of ##STR68## were charged. The intrinsic viscosity of this resinwas 0.49; elemental analysis indicated the presence of 3.5 weightpercent silicone.

EXAMPLE 7 Silicone-modified-polyester Resin

The procedure of Example A was followed with the exception that 32.0grams of ##STR69## where charged. The intrinsic viscosity of this resinwas 0.62; elemental analysis indicated the presence of 3.9 weightpercent silicone.

EXAMPLE 8 Silicone-modified-polyester Resin

The procedure of Example A was followed with the exception that 32.0grams of ##STR70## were charged. In addition, stirrer rates were changedin the following manner: (1) stirring was maintained initially at 250rpm for 30 minutes, (2) after 30 minutes stirring rate was reduced to150 rpm and maintained for the remainder of the polymerization. Theintrinsic viscosity of this resin was 0.57; elemental analysis indicatedthe presence of 3.4 weight percent silicone.

EXAMPLE 9 Silicone-modified-polyester Resin

The procedure of Example 2 was followed with the exception that stirringrates were changed in the following manner: (1) stirring was maintainedat 250 rpm for 1 hour, (2) after 1 hour stirring rate was reduced to 150rpm and maintained for the remainder of the polymerization. Theintrinsic viscosity of this resin was 0.62; elemental analysis indicatedthe presence of 4.4 weight percent silicone.

EXAMPLES 10 TO 29 Silicone-modified-polyester Resin

The procedure of Example A was followed with the exception that 32.0grams of ##STR71## was charged with the other reactants and catalysts,where a,b,x and Z are defined in Table A.

                                      TABLE A                                     __________________________________________________________________________                          Average                                                                              Intrinsic                                                                          % Wt.                                       Example                                                                            a  b  x Z        Domain Size                                                                          Viscosity                                                                          Silicon                                     __________________________________________________________________________    10   5  70 0 C.sub.2 H.sub.5                                                                        24     0.80 2.9                                         11   5  70 0 C.sub.6 H.sub.13                                                                       6.2    0.76 2.7                                         12   5  70 0 C.sub.8 H.sub.17                                                                       5.0    0.58 2.9                                         13   5  70 0 C.sub.10 H.sub.21                                                                      5.3    0.58 2.4                                         14   5  70 0 C.sub.12 H.sub.25                                                                      5.0    0.41 3.1                                         15   5  70 0 C.sub.18 H.sub.37                                                                      1      0.54 2.8                                         16   5  70 3 N(C.sub.4 H.sub.8)                                                                     13     0.60 3.2                                         17   5  70 3 OC.sub.2 H.sub.4 OC.sub.4 H.sub.9                                                      22     0.68 2.5                                         18   5  70 3 O(C.sub.2 H.sub.4 O).sub.3 CH.sub.3                                                    22     0.67 2.7                                         19   5  70 3 O(C.sub.3 H.sub.6 O).sub.6.3 CH.sub.3                                                  28     0.57 2.7                                         20   5  70 3 O(C.sub.3 H.sub.6 O).sub.3 CH.sub.3                                                    <1     0.72 3.0                                         21   5  70 2 CF.sub.3 <20    0.55 2.8                                         22   5  70 2 C.sub.8 F.sub.17                                                                       7.3    0.71 3.0                                         23   7.5                                                                              67.5                                                                             0 C.sub.12 H.sub.25                                                                      3.4    0.57 2.9                                         24   2.5                                                                              72.5                                                                             0 C.sub.12 H.sub.25                                                                      7.5    0.67 2.6                                         25   2.5                                                                              72.5                                                                             0 C.sub.18 H.sub.37                                                                      2.7    0.66 2.9                                         26   5  70 0 C.sub.6 H.sub.5                                                                        7      0.49 2.5                                         27   5  70 3 CN       8.5    0.65 2.3                                         28   5  70 2 C.sub.6 H.sub.5                                                                        16     0.63 2.4                                         29   10 65 2 C.sub.6 H.sub.5                                                                        11     0.82 3.0                                         __________________________________________________________________________

PROCEDURE B Unmodified Poly(ethyleneterephthate) Resin

A stainless steel reactor was equipped with a mechanical stirrer (ModelHST 20; G. K. Heller Corp.), condenser and argon sparge. To this reactorwas charged 150 grams of dimethylterephthalate (DMT) and 119 grams ofethylene glycol (EG). Then, 0.05 grams of manganese acetate and 0.06grams of antimony oxide were added as catalysts. Using an electricalheating mantel, the reactor temperature was brought to 175° C. andstirring at 50 rpm was initiated. Subsequently, the temperature wasraised to 200° C. and held at this temperature for 1.5 hours to effecttransesterification. At the end of this interval, approximately 80percent of the theoretical quantity of methanol had evolved.Subsequently, the reactor temperature was raised to approximately 240°C. and maintained at this temperature for approximately 1 hour. At theend of this interval, an additional 20 percent of theoretical methanolhas been collected, bringing the total up to 100 percent of thetheoretical quantity. At this point, the stirring rate was reduced to 25RPM and the reactor temperature was gradually increased to 275° C.-280°C. while pressure was slowly reduced to approximately 0.2 mmHg. Theprogress of polymerization was monitored by the torque required tomaintain a constant stirring rate. Initial torque readings weretypically 3-4 pounds-inch. When torque had increased to approximately 25pounds-inch, stirring was stopped and reaction pressure was raised toatmospheric by bleeding in argon. Using a slight positive pressure, themolten resin was discharged into water. The intrinsic viscosity of thisresin (measured in a solvent of 1 part by weight of trifluoroacetic acidand 3 parts by weight of dichloromethane) was 0.50.

EXAMPLE 30 Silicone-modified Polyester Resin

The procedure of Example A is followed with the exception that 32.0grams of ##STR72## is charged with the other reagents and catalysts. Itis anticipated that the domain size will reflect the enhanced solubilityof the silicone in the polyester.

EXAMPLE 31 Silicone Modified-polyester Resin

Procedure B was followed with the exception that 6.5 grams of ##STR73##was charged. Fibers pulled from molten resin could be cold drawn by afactor of 10×.

EXAMPLE 32 Silicone-Modified-polyester Resin

Procedure B was followed with the exception that 13.0 grams of ##STR74##was charged. Fibers pulled from often resin could be cold drawn by afactor of 8×.

EXAMPLE HH Silicone-Modified-polyester Resins

Procedure B was followed with the exception that 20.0 grams of ##STR75##was charged. The final product could not be discharged into water. Onopening the hot reactor apparatus, a rubbery molten mass was discovered.Attempts to pull fibers from this mass were unsuccessful.

EXAMPLE 32 Silicone-Modified-polyester Resin

Procedure B was followed with the exception that 20 grams of ##STR76##was charged. The final product was highly viscous but was successfullydischarged into water. Fiber samples were pulled from the molten resin.Due to the fact that the pull occurred at too low a temperature abrittle fiber resulted that was unable to be drawn.

EXAMPLE 34 Silicone-Modified-polyester Resin

The following procedure, which is based on early experiments in polymersynthesis, is a technique for probing the incorporation of silicone intopolyester resin.

A clean, dry glass polymerization tube was charged with 38.8 grams ofdimethylterephthalate (DMT), 31.2 grams of ethylene glycol (EG), 216 μlof a 5 weight percent solution of Zn(OAc)₂.2H2O in ethylene glycol, 12μl of ethylantimonate (III) and the desired quantity of ##STR77## Then,the polymerization tube and contents were placed in a fluidized sandbath. A mild argon sparge was admitted through an inlet. The temperaturewas then raised to 180° C. and held there for three hours. During thisstep, transesterification of DMT with EG occurs and by-product methanolwas distilled off. Subsequently, the temperature was increased to 230°C. and held there for one hour. During this operation, excess EG wasremoved from the reaction mass. With this step completed, thetemperature was elevated to 275° C.-280° C. During this period, theargon sparge was lowered into the system until it reached a depth of 1-2mm. Caution is advised during this operation because certain modifierstend to cause undue foaming of the melt. The polycondensation step wasallowed to proceed under these conditions for about three hours. At theend of the polymerization, the apparatus was brought to atmosphericpressure using argon and the polymerization tube pulled from the bath tocool. The polymer was then recovered by breaking away the glass.

Fibers were obtained by pulling filaments from a melt of chips ofrecovered resin at 280° C.-290° C. under a blanket of argon using aglass rod as a probe. The fibers so obtained would cold draw to severaltimes their length if the molecular weight was sufficiently high.

EXAMPLE 35 Silicone-modified Poly(Butyleneterephthalate)

Procedure B was followed with the exception that the following werecharged:

(1) 208 grams of 1,4-butanediol (no ethylene glycol was charged)

(2) 0.1 grams of tetra isopropyltitanate

(3) 6.5 grams of ##STR78## Because of the low melting point ofpoly(butyleneterephthalate), the reactor temperature is maintained at260° C. Samples of fibers pulled from molten resin could be cold drawnby a factor of 8×.

Domain Size Determination

Samples of resin were fractured and sputtered with gold to a thicknessof approximately 300 Angstroms (A). Using a Hitachi Model S-450 scanningelectron microscope operating at approximately 20 kilovolts acceleratingvoltage, Polaroid photographs of typical fracture surfaces were taken atapproximately 1200× magnification. Domain sizes were measured from thephotographs and reported as mean, maximum, and minimum values. The meandomain size was determined from twenty randomly selected domains.

Electron Spectroscopy for Chemical Analysis (ESCA) Fiber SurfaceCharacterization

ESCA data were obtained using a Perkin-Elmer Electronics Division Model550 spectrometer. The excitation radiation was generated using anachromatic Mg anode x-ray source operating at 15 KV and 20 mA with anenergy of 1253.6 electron volts (ev) (Mg Kα).

Survey scans of each sample were collected at a pass energy of 100 ev.In addition, higher resolution spectra of individual photoelectron linesof interest such as Si(2p) were collected at a pass energy of 50 ev.

The binding energy scale of the spectrometer was calibrated to theAu(4f) 7/1 line at 83.8 ev. Additional static charge corrections weremade using the adventitious carbon (1s) line at 284.6 ev.

Under the operating conditions used, the spectrometer analysis area wasa circular region with an approximate diameter of 6-7 mm. This largeanalysis area required special specimen preparation methods sinceindividual fiber diameters were approximately 20 microns.

Specimens were prepared by wrapping polyester filament around a 1 sq. cmsection of high purity aluminum foil. The aluminum foil had beenpreviously washed in hexane, argon-ion sputtered and analyzed by xps toensure that surface contamination by carbon and oxygen had beenminimized.

Specimens were attached to a stainless steel xps sample holder andplaced onto the spectrometer's (introduce) rod. Then specimens weremoved into the pre-pump chamber where they were evacuated for 15 minutesto a pressure of approximately 1×10⁻⁶ torr. They were then introducedinto analysis chambers of the spectrometer which was maintained to apressure of approximately 8×10⁻⁹ torr.

During the analysis it became evident that the aluminum foil was notcompletely covered by polyester filament since low concentrations ofaluminum were invariably observed in fiber spectra. However, since A12pand A12s photoelectron lines do not overlap any of the photoelectronlines generated from experimentions specimens, the results of siliconedeterminates were unaffected.

                  TABLE 1                                                         ______________________________________                                        Effect of Silicone Molecular Weight of                                        Poly(ethylene terephthalate)/Silicone                                         Copolymer Surface Energy                                                                             Contact Angle On                                       Composition.sup.1      Resin Surface.sup.2                                    ______________________________________                                        PET.sup.3              70°                                              ##STR79##             70°                                              ##STR80##             70°                                              ##STR81##             80°                                              ##STR82##             90°                                             Teflon ™            90°                                             ______________________________________                                         .sup.1 Copolymers contained five weight percent silicone.                     .sup.2 Water/ --iso-propyl alcohol.                                           .sup.3 Poly(ethylene terephthalate)                                      

                  TABLE 2                                                         ______________________________________                                        Thermal Transitions of Resin                                                                       Glass   Glass                                                                 Trans-  Trans-  Melt-                                                         ition   ition   ing                                                           Temp.   Temp.   Point                                    Composition.sup.1    (°C.)                                                                          (°C.)                                                                          PET                                      ______________________________________                                        PET                  --      85      256                                       ##STR83##           -112    70      248                                       ##STR84##           -117    82      256                                      ______________________________________                                         .sup.1 Copolymeric resins contain five weight percent silicone.          

                                      TABLE 3                                     __________________________________________________________________________    Fiber Physical Properties                                                                          Tenacity       Modulus                                   Composition.sup.1    (grams/denier)                                                                        Elongation %                                                                         (grams/denier)                            __________________________________________________________________________    PET                  2.8     167    25                                         ##STR85##           2.6     143    23                                         ##STR86##           2.1     151    22                                        __________________________________________________________________________     .sup.1 Copolymeric resins contain five weight percent silicone.          

                  TABLE 4                                                         ______________________________________                                        ESCA (Electron Spectroscopy for Chemical                                      Analysis) Fiber Surface Characterization                                                            Weight Percent                                                                Silicone                                                                      On Fiber Surface                                                              Fiber State                                             Composition.sup.1       Undrawn  Drawn                                        ______________________________________                                        PET                     15       --                                            ##STR87##              49       86                                            ##STR88##              57       78                                           ______________________________________                                         .sup.1 Fiber contains 5.0 weight percent silicone based on reactants          charged.                                                                 

                                      TABLE 5                                     __________________________________________________________________________    Effect of Agitation Rate and                                                  Endblocker on Domain Size                                                                                    Agitation                                                                     Speed   Domain Diameter (μ)                 Silicone-co-polyester          (RPM)                                                                              IV.sup.(1)                                                                       Maximum                                                                             Minimum                                                                            Mean                        __________________________________________________________________________     ##STR89##                     50   0.60                                                                             131   36   69                           ##STR90##                     250  0.70                                                                             1     0.2  0.5                          ##STR91##                     250/150                                                                            0.62                                                                             2     0.2  0.4                          ##STR92##                     50   0.51                                                                             15     2    6                           ##STR93##                     50   0.55                                                                             3     0.2  0.7                         __________________________________________________________________________     .sup.(1) Intrinsic Viscosity.                                                 .sup.(2) High agitation rate used during glycol strip and initial             polycondensation; lower rate used during latter stage of polycondensation                                                                              

What is claimed is:
 1. A process for preparing a silicone-modifiedpolyester resin comprising reacting an aromatic dicarboxylic acid or itsdiester, a diol and a siloxane block polymer of the general formula:##STR94## wherein R is individually a monovalent group selected from thegroup consisting of alkyl, aryl, acyl, aralkyl and polyoxyalkylgroups;R' is individually a monovalent group selected from the groupconsisting of alkyl, aryl, alkenyl, and aralkyl groups containing from 1to 8 carbon atoms; Z is selected from the group consisting of alkyl,aryl, aralkyl, alkoxy, polyoxyalkyl, alkenyl and siloxy with the provisothat when Z is siloxy x must equal zero; a has a value of 0 to 10; b hasa value of 0 to 50,000; c has a value of 0 to 1,000 and the sum of a+b+cis such that the siloxane block polymer contains at least 9; siliconatoms; and x has a value of 0, 1, 2 or 3; wherein said reaction takesplace in two stages, the first stage being either a transesterificationbetween the diester of the dicarboxylic acid and the diol and siloxaneblock polymer or an esterification between the dicarboxylic acid and thediol and siloxane block polymer, the second stage being apolycondensation reaction of the transesterification or esterificationproduct wherein said siloxane block polymer constitutes from 0.1 to 10weight percent, based on the total reaction product and forms uniformdomains approximately 0.05 to 6 micron in average size.
 2. The processof claim 1 wherein the aromatic dicarboxylic acid is selected from thegroup of aromatic dicarboxylic acids having 8 to 15 carbon atoms.
 3. Theprocess of claim 1 wherein the diester of an aromatic dicarboxylic acidis selected from the group of C₁ to C₄ dialkyl esters of aromaticdicarboxylic acids having 8 to 15 carbon atoms.
 4. The process of claim2 wherein the aromatic dicarboxylic acid is symmetrical.
 5. The processof claim 4 wherein the aromatic dicarboxylic acid is terephthalic acid.6. The process of claim 3 wherein the ester of the aromatic dicarboxylicacid is dimethylterephthalate.
 7. The process of claim 1 wherein thediol has from 2 to 20 carbon atoms.
 8. The process of claim 7 whereinthe diol is selected from the group consisting of branched or unbranchedaliphatic diols, bis(hydroxyphenyl)alkanes, di(hydroxyphenyl)sulfonesand di(hydroxyphenyl)ethers.
 9. The process of claim 8 wherein the diolis an aliphatic diol.
 10. The process of claim 9 wherein the diol isethylene glycol.
 11. The process of claim 1 wherein the siloxane blockpolymer is such that R is an oleophillic group containing from 1 to 18carbon atoms.
 12. The process of claim 11 wherein R contains from 1 to12 carbon atoms.
 13. The process of claim 12 wherein R is either ethylor 2-ethylhexyl.
 14. The process of claim 1 wherein the siloxane blockpolymer is such that R' is an oleophillic group containing from 1 to 8carbon atoms.
 15. The process of claim 14 wherein R' is an alkyl group.16. The process of claim 15 wherein R' is methyl.
 17. The process ofclaim 1 wherein the siloxane block polymer is such that Z is anoleophillic group containing from 1 to 25 carbon atoms.
 18. The processof claim 17 wherein Z is an oleophillic group containing from 1 to 15carbon atoms.
 19. A process for preparing a silicone-modified polyesterresin comprising reacting an aromatic dicarboxylic acid or its diester,a diol and a siloxane block polymer of the general formula: ##STR95##wherein R is individually a monovalent group selected from the groupconsisting of alkyl, aryl, acyl, aralkyl and polyoxyalkyl groups;R' isindividually a monovalent group selected from the group consisting ofalkyl, aryl, alkenyl, and aralkyl groups consisting of alkyl, aryl,alkenyl, and aralkyl groups containing from 1 to 8 carbon atoms; Z is anoleophillic group containing from 1 to 15 carbon atoms selected from thegroup consisting of alkyl, aryl, aralkyl, alkoxy, polyoxyalkyl, alkenyland siloxy, while oleophillic group is substituted with a group selectedfrom the group consisting of halogen, cyano, amino, carboxy, sulfonate,alkylmercapto and hydroxy with the proviso that when Z is siloxy x mustequal zero; a has a value of 0 to 10; b has a value of 0 to 50,000; chas a value of 0 to 1,000 and the sum of a+b+c is such that the siloxaneblock polymer contains at least 9 silicon atoms; and x has a value of 0,1, 2 or 3; wherein said reaction takes place in two stages, the firststage being either a transesterification between the diester of thedicarboxylic acid and the diol and siloxane block polymer or anesterification between the dicarboxylic acid and the diol and siloxaneblock polymer, the second stage being a polycondensation reaction of thetransesterification or esterification product wherein said siloxaneblock copolymer constitutes from 0.1 to 10 weight percent, based on thetotal reaction product and forms uniform domains approximately 0.05 to 6micron in average size.
 20. The process of claim 1 wherein the siloxaneblock polymer is such that a has a value of 0 to
 5. 21. The process ofclaim 1 wherein the siloxane block polymer is such that b has a value offrom 10 to 10,000.
 22. The process of claim 21 wherein b has a value offrom 50 to
 200. 23. The process of claim 1 wherein the siloxane blockpolymer is such that c has a value of from 0 to
 100. 24. The process ofclaim 23 wherein c is zero.
 25. The process of claim 1 wherein thesiloxane block polymer is such that R is 2-ethylhexyl, a is 0, b is 75,and c is zero.
 26. The process of claim 1 wherein the siloxane blockpolymer is such that R is 2-ethylhexyl, R' is methyl, Z is CH₃ O(C₂ H₄O)₆.3, a is 5, b is 70, c is zero and x is
 3. 27. The process of claim 6wherein the siloxane block polymer is such that R is ethyl, R' ismethyl, Z is --CH₂ CH₂ CF₃, a is 5, b is 70, c is zero and x is zero.28. The process of claim 1 wherein the siloxane block polymer is suchthat R is ethyl, R' is methyl, Z is --C₂ H₄ C₆ H₅, a is 10, b is 65, cis zero and x is zero.
 29. The process of claim 1 wherein the siloxaneblock polymer is such that R is ethyl, R' is methyl, Z is --C₁₅ H₃₁, ais 5, b is 70, c is zero, and x is
 3. 30. The process of claim 19wherein the siloxane block polymer is such that R is ethyl, R' ismethyl, Z is ##STR96## a is 5, b is 70, c is zero and x is
 3. 31. Asilicone-modified polyester resin comprising:(a) a polyester matrixcomprising the reaction product of an aromatic dicarboxylic acid or itsdiester and a diol; (b) a silicone-modified polyester matrix comprisingthe reaction product of an aromatic dicarboxylic acid or its diester, adiol and a siloxane-block polymer of the general formula: ##STR97##wherein R is individually a monovalent group selected from the groupconsisting of alkyl, aryl, acyl, aralkyl and polyoxyalkyl groups;R' isindividually a monovalent group selected from the group consisting ofalkyl, aryl, alkenyl and aralkyl groups containing from 1 to 8 carbonatoms; Z is selected from the group consisting of alkyl, aryl, aralkyl,alkoxy, polyoxyalkyl, alkenyl and siloxy with the proviso that when Z issiloxy x must equal zero; a has a value of 0 to 10; b has a value of 0to 50,000; c has a value of 0 to 1,000 and the sum of a+b+c is such thatthe polysiloxane block polymer contains at least 9 silicon atoms; and xhas a value of 0, 1, 2 or 3; and (c) optionally a polysiloxane blockpolymer wherein said silicone-modified polyester matrix is dispersedthroughout the polyester matrix as microdomains of between 0.05 to 6micron size and contain, when present, encapsulated polysiloxane blockpolymer.
 32. The resin of claim 31 wherein the aromatic dicarboxylicacid is selected from the group of aromatic dicarboxylic acids having 8to 15 carbon atoms.
 33. The resin of claim 31 wherein the diester of anaromatic dicarboxylic acid is selected from the group of C₁ to C₄dialkyl esters of aromatic dicarboxylic acids having 8 to 15 carbonatoms.
 34. The resin of claim 32 wherein the aromatic dicarboxylic acidis symmetrical.
 35. The resin of claim 34 wherein the aromaticdicarboxylic acid is terephthalic acid.
 36. The resin of claim 33wherein the ester of the aromatic dicarboxylic acid isdimethylterephthalate.
 37. The resin of claim 31 wherein the diol hasfrom 2 to 20 carbon atoms.
 38. The resin of claim 37 wherein the diol isselected from the group consisting of branched or unbranched aliphaticdiols, bis(hydroxyphenyl)alkanes, di(hydroxyphenyl)sulfones anddi(hydroxyphenyl)ethers.
 39. The resin of claim 38 wherein the diol isan aliphatic diol.
 40. The resin of claim 39 wherein the diol isethylene glycol.
 41. The resin of claim 31 wherein the siloxane blockpolymer is such that R is an oleophillic group containing from 1 to 18carbon atoms.
 42. The resin of claim 41 wherein R contains from 1 to 12carbon atoms.
 43. The resin of claim 42 wherein R is either ethyl or2-ethylhexyl.
 44. The resin of claim 41 wherein the siloxane blockpolymer is such that R' is an oleophillic group containing from 1 to 8carbon atoms.
 45. The resin of claim 44 wherein R' is an alkyl group.46. The resin of claim 45 wherein R' is methyl.
 47. The resin of claim31 wherein the siloxane block polymer is such that Z is an oleophillicgroup containing from 1 to 25 carbon atoms.
 48. The resin of claim 47wherein Z is an oleophillic group containing from 1 to 15 carbon atoms.49. A silicone-modified polyester resin comprising:(a) a polyestermatrix comprising the reaction product of an aromatic dicarboxylic acidor its diester and diol; (b) a silicone-modified polyester matrixcomprising the reaction product of an aromatic dicarboxylic acid or itsdiester, a diol and a siloxane-block polymer of the general formula:##STR98## wherein R is individually a monovalent group selected from thegroup consisting of alkyl, aryl, acyl aralkyl and polyoxyalkyl groups;R' is individually a monovalent group selected from the group consistingof alkyl, aryl, alkenyl and aralkyl groups containing from 1 to 8 carbonatoms; Z is an oleophillic group containing from 1 to 15 carbon atomsselected from the group consisting of alkyl, aryl, aralkyl, alkoxy,polyoxyalkyl, alkenyl and siloxy which oleophillic group is substitutedwith a group selected from the group consisting of halogen, cyano,amino, carboxy, sulfonate, alkylmercapto and hydroxy with the provisothat when Z is siloxy x must equal zero; a has a value of 0 to 10; b hasa value of 0 to 50,000; c has a value of 0 to 1,000 and the sum of a+b+cis such that the siloxane block polymer contains at least 9 siliconatoms; and x has a value of 0, 1, 2, 3; and (c) optionally apolysiloxane block polymer wherein said silicone-modified polyestermatrix is dispersed throughout the polyester matrix as microdomains ofbetween 0.05 to 6 micron size and contain, when present, encapsulatedpolysiloxane block polymer.
 50. The resin of claim 31 wherein thesiloxane block polymer is such that a has a value of 0 to
 5. 51. Theresin of claim 31 wherein the siloxane block polymer is such that b hasa value of from 10 to 10,000.
 52. The resin of claim 51 wherein b has avalue of from 50 to
 200. 53. The resin of claim 31 wherein the siloxaneblock polymer is such that c has a value of from 0 to
 100. 54. The resinof claim 53 wherein c is zero.
 55. The resin of claim 31 wherein thesiloxane block polymer is such that R is 2-ethylhexyl, a is 0, b is 75,and c is zero.
 56. The resin of claim 31 wherein the siloxane blockpolymer is such that R is 2-ethylhexyl, R' is methyl, Z is CH₃ O(C₂ H₄O)₆.3, a is 5, b is 70, c is zero and x is
 3. 57. The resin of claim 7wherein the siloxane block polymer is such that R is ethyl, R' ismethyl, Z is --CH₂ CH₂ CF₃, a is 5, b is 70, c is zero and x is zero.58. The resin of claim 31 wherein the siloxane block polymer is suchthat R is ethyl, R' is methyl, Z is --C₂ H₄ C₆ H₅, a is 10, b is 65, cis zero and x is zero.
 59. The resin of claim 31 wherein the siloxaneblock polymer is such that R is ethyl, R' is methyl, Z is --C₁₅ H₃₁, ais 5, b is 70, c is zero, and x is
 3. 60. The resin of claim 7 whereinthe siloxane block polymer is such that R is ethyl, R' is methyl, Z is##STR99## a is 5, b is 70, c is zero and x is 3.